The heart muscle is surrounded by tissue known as the pericardial sac, which consists of several layers of tissue. The outermost of these layers is the fibrous pericardium. Inside the fibrous pericardium is the serous pericardium. The serous pericardium consists of three parts: the parietal pericardium, which is bonded to the inside of the fibrous pericardium; the innermost visceral pericardium; and a fluid-containing potential space between the parietal pericardium and the visceral pericardium called the pericardial space. Inside the visceral pericardium is the myocardium, the actual heart muscle itself.
Epicardial procedures on the heart are growing in number, efficacy, and complexity. Currently, ablations for ventricular tachycardia and atrial fibrillation as well as intra-cardiac procedures for valve repair are done using approaches on the outside of the heart. Establishing epicardial access is often difficult and frequently requires the assistance of a surgeon. Similar difficulties exist in establishing access to other anatomical spaces with surfaces, such as the kidneys, the dura mater of the brain, blood vessels, and the peritoneum.
Several conventional devices establish access to such anatomical spaces using vacuum or forceps. One problem with vacuum designs is that it is difficult to maintain the vacuum seal on the pericardium required to create and uphold a bleb. Additionally, if the vacuum seal is broken, the tissue bleb may re-collapse away from the tip of the suction probe, thus interrupting the procedure. Vacuum suction is also likely to cause trauma and scarring to the pericardium. Moreover, vacuum designs are likely to clog on other bodily tissues encountered before reaching the pericardium. Forceps designs also pose several problems. First, forceps designs provide an uncertain grasp on the pericardium. Second, forceps devices require such shallow approach angles that they often have difficulty grasping the pericardium. Moreover, such forceps devices require that large incisions be made in the subject in order to provide a large enough window to facilitate their use.
Conventional approach with penetration devices and access tubes do not grip the anatomical surface with uniform force, increasing the risk of tearing. Additionally, significant mechanical difficulties are encountered with fat and other tissue in the body before reaching the anatomical surface, as fat and tissue may become caught in the penetrating elements and restrict further movement.
There is therefore a need in the art for a safe, consistent, accurate, and easy to use percutaneous system to access the pericardial space. Similar needs arise in the context of accessing other anatomical spaces with surfaces as well.